Apparatus for grinding film sprockets



Sept. 17, 1929.

F. H. OWENS 1,728,441

APPARATUS FOR GRINDING FILM SPROCKETS I Filed July 13. 1927 2 Sheets-Shee l' Sept. 17, 1929. F H, @WENS 1,728,441

APPARATUS FOR GRINDING FILM SPROCKETS Filed July l5, 1927 2 Sheets-Sheet 2 Patented Sept. 17, 1929 PATENT OFFICE FREEMAN H. OWENS, OF NEW YORK, N. Y.

APPARATUS'FOR GRINDING FILM SPROGKETS Applicationled vJ'uly 1.3,

ln the art of photographically recording sound and reproducing the same, particularly when such sound is combined with motion pictures, itis absolutely essential that the film feeding be accurate so that the tilm will be moved at a constant and uniform speed.

One of the most important. features of such film feeding mechanism is the sprocket for moving the film. This sprocket must be perfectly true with respect to the shaft upon which it is lnounted. In order to provide and insure the required accuracy, I have devised the following apparatus for grinding sprockets to be used for this purpose.

Heretofore, it has been customary to cut or grind sprockets on a shaft mounted and rotated between centers. Such apparatus has not proven of suiicient accuracy for sprockets to be used for the above mentioned purpose due to the fact that so frequently the centers are out of adjustment or that the shaft is not properly aligned, resulting in an imperfectly ground sprocket.

The primary object of my invention is to provide an apparatus for grinding the sprockets of this character. wherein the shaft upon which the sprocket is to be mounted and used in the tilm feeding mechanism, is supported in bushings and rotated therein, and a rotatable grinder applied to said sprocket and adjustable with respect thereto.

Another object is to provide a novel form of supporting mechanism for apparatus for grinding film feeding sprockets.

Other objects and advantages in details of construction and operation will be apparent as the description proceeds, reference now being had to theligures of the drawings, wherein like reference numerals indicate like parts Figure 1 i tus.

Figure 2 is a detail cross section.

Figure 3 is a side view 0f the apparatus.

Figure 4 is an end view thereof.

The reference numeral 1 indicates a base member or support upon which is mounted an upwardly extending frame 2 provided with the extensions 3, carrying at their u er ends 50 the bushings or bearings 4 adaptagije s a front view of my new apparato re- 1927. Serial No. 205,445.

ceive the rotatable shaft 5, carrying at one end the sprocket 6, secured on such shaft by means yof the lock nut 7 and keyed for rotation with the shaft b means of the pin 8 carried in the flange 9 o the shaft and entering a suitable opening in the end of the sprocket. The opposite end of the shaft 5 is provided with. a pulley 10 around which passes a belt 11 engaging also around a pulley 12 onlthe shaft of the motor or. other source of power 13. The pulley 10 is preferably removable from the shaft 5 so that the sprocket and shaft in its entlrety may be removed from the bearing 4. The shaft 5 is preferably the same shaft upon which the sprocket 6 is mounted in the film feeding mechanismv (not shown), in v which the sprocket plays an important part in the proper feeding of the photographic lm bearing sound records.

.The base member 1 is provided with a dove tall groove 14 in which is slidably mounted a support 15 provided with an upstanding frame 16 carrying the sprocket grinding element to be described. The support 15 may be moved on the base 1 by means of an elongated screw 17 engaging at one end in the extension 16 and passing through the threaded bearing 18 mounted on the base 1 and provided with a knurled thumb piece or manipulating member 19. A second bearing 20 is carried by the sliding support 15 and the screw 17 likewise passes through this bearmg.

The upper end of the upwardly extending frame 16 is provided with a dove tail groove 21 in which is mounted ay slide 22 provided with outwardly extending arms 23, the outer ends of which carry bearings 24. Rotatably mounted in these bearings 24 is a shaft 25 carrying at one end a pulley 26 over which passes a belt 27, also passing over a relatively large pulley 28 on the shaft of a motor 29 mounted on a bracekt 30, on the upstanding frame 16. Also mounted on the shaft 25 at a point between the bearings 24 and properly spaced therefrom by the washers 31 is a grind- Ilngv wheel 32, the periphery of which is in operative position with respect to the sprocket 6.

The slide 22 is provided with a bracket 33 through which extends downwardly a screw 34 engageable at its lower end in a threaded bearing 35 carried by the slide. A hand wheel 36 is carried at the upper end of the screw 34 whereby this slide 22 may be moved upwardly and downwardly in thedove tail 21. The hand wheel 36 may be graduated and a pointer 37 provided for such graduations to indicate the amount of movement of the slide.

- In the operation of my invention, the shaft 5 with the sprocket 6 thereon is placed in position in the bearings 4 and the pulley 10 secured thereon and connected by the belt 11 to the motor 13. The screw 17 is then manipulated to bring the upstanding frame 16 carryingthe grinder 32 into proper longitudinal position with respect to the sprocket 6, that is, on one side or another of the teeth of the 20 sprocket and then the hand Wheel 36 is oper-l ated to raise or lower the slide 22 to bring the grinder into engagement with the sprocket. A. spring pressed belt tensioning device of any suitable character, indicated at 38, may 25 be provided to at all times keep the belt 27 at proper driving tension, regardless of the position of the slide 22.

In Figure 1, there is shown in dotted lines the various positions to which the grinder 3o wheel may be moved with respect to the sprocket for the grinding operation. The vertical adjustment of the grinder permits raising the same to a height sui'icient to clear the teeth when shifting the same longitudinally of the sprocket.

' Of course, many changes may be made by Way of detail, without departing from the spirit and scope of my invention. I do not limit myself, therefore, to the exact structure 40 shown and described other than by the appended claim. I claim A grinder comprising in combination a base, an upstanding upright integral with said base,`a laterally movable upstanding upright member mounted u on said base, a screw arrangement for shi ing the position of said movable upright member with respect to the base, a bearing support slidably mounted upon said movable upright member, a graduated screw arrangement mounted upon said movable upright member for varying the position of the said bearing support with respect to the movable upright member, a shaft having a grinding wheel attached thereto rotatably mounted in said bearing support, a second shaft rotatably mounted in bearings upon said inte ral upright said second shaft being adapte to removably hold a film sprocket in the process of grinding.

FREEMAN H. OWENS. 

